Poly(aryl ether ketones) are known materials which display exceptional high temperature performance. They are crystalline polymers with melting points above 300.degree. C. Two of these crystalline poly(aryl ether ketones) are commercially available and are of the following structure: ##STR1##
Over the years, there has been developed a substantial body of patent and other literature directed to formation and properties of poly(aryl ethers) (hereinafter called "PAE"). Some of the earliest work, such as by Bonner, U.S. Pat. No. 3,065,205 involves the electrophilic aromatic substitution (e.g., Friedel-Crafts catalyzed) reaction of aromatic diacylhalides with unsubstituted aromatic compounds such as diphenyl ether. The evolution of this class to a much broader range of PAE's was achieved by Johnson et al., Journal of Polymer Science, A-1, Vol. 5, 1967, pp. 2415-2427; Johnson et al., U.S. Pat. Nos. 4,107,837 and 4,175,175. Johnson et al. show that a very broad range of PAE's can be formed by the nucleophilic aromatic substitution (condensation) reaction of an activated aromatic dihalide and an aromatic diol. By this method, Johnson et al. created a host of new PAE's including a broad class of poly(aryl ether ketones), hereinafter called "PAEK's".
In recent years, there has developed a growing interest in PAEK's as evidenced by Dahl, U.S. Pat. No. 3,953,400; Dahl et al., U.S. Pat. No. 3,956,240; Dahl, U.S. Pat. No. 4,247,682; Rose et al., U.S. Pat. No. 4,320,224; Maresca, U.S. Pat. No. 4,339,568; Atwood et al., Polymer, 1981, Vol. 22, August, pp. 1096-1103; Blundell et al., Polymer 1983, Vol. 24, August, pp. 953-958; Atwood et al., Polymer Preprints, 20, No. 1, April 1979, pp. 191-194; and Rueda et al., Polymer Communications, 1983, Vol. 24, September, pp. 258-260. In early to mid-1970, Raychem Corporation commercially introduced a PAEK called Stilan.RTM., a polymer whose cronym is PEK, each ether and keto group being separated by 1,4-phenylene units. In 1978, Imperial Chemical Industries PLC (ICI) commercialized a PAEK under the trademark Victrex PEEK. As PAEK is the acronym of poly(aryl ether ketone), PEEK is the acronym of poly(ether ether ketone) in which the 1,4-phenylene units in the structure are assumed.
Thus, PAEK's are well known; they can be synthesized from a variety of starting materials; and they can be made with different melting temperatures and molecular weights. The PAEK's are crystalline, and as shown by the Dahl and Dahl et al. patents, supra, at sufficiently high molecular weights they can be tough, i.e., they exhibit high values (&gt;50 ft-lbs/in.sup.2) in the tensile impact test (ASTM D-1822). They have potential for a wide variety of uses, but because of the significant cost to manufacture them, they are expensive polymers. Their favorable properties class them in the upper bracket of engineering polymers.
PAEK's may be produced by the Friedel-Crafts catalyzed reaction of aromatic diacylhalides with unsubstituted aromatic compounds such as diphenyl ether as described in, for example, U.S. Pat. No. 3,065,205. These processes are generally inexpensive processes; however, the polymers produced by these processes have been stated by Dahl et al., supra, to be brittle and thermally unstable. The Dahl patents, supra, allegedly depict more expensive processes for making superior PAEK's by Friedel-Crafts catalysis. In contrast, PAEK's such as PEEK made by nucleophilic aromatic substitution reactions are produced from expensive starting fluoro monomers, and thus would be classed as expensive polymers.
These poly(aryl ether ketones) exhibit an excellent combination of properties; i.e., thermal and hydrolytic stability, high strength and toughness, wear and abrasion resistance and solvent resistance. Thus, articles molded from poly(aryl ether ketones) have utility where high performance is required. However, in some applications, such as those where the poly(aryl ether ketone) is to be used as a thermoplastic composite matrix resin, its glass transition temperature (Tg) may not be as high as desired for the particular application. This is because polymers, even crystalline polymers, exhibit excessive loss of modulus, strength and creep resistance above their Tg's. This loss in properties may not be acceptable in cases where the materials are to be used as thermoplastic composite matrix resins.
In order to alleviate this situation, various miscible blends of the PAEK's with other thermoplastics, having higher glass transition temperatures than the poly(aryl ether ketones), have been developed.
It is known, that polymers are generally immiscible, and that it is for all practical purposes, impossible to predict whether a given polymer pair will yield a miscible blend. However, according to Olabisi, et al., Polymer-Polymer Miscibility, 1979, published by Academic Press, New York, N.Y., p. 120:
"The most commonly used method for establishing miscibility in polymer-polymer blends or partial phase mixing in such blends is through determination of the glass transition (or transitions) in the blend versus those of the unblended constituents. A miscible polymer blend will exhibit a single glass transition between the Tg's of the components with a sharpness of the transition similar to that of the components." PA1 (i) at least one bisphenol, and PA1 (ii) at least one dihalobenzenoid compound and/or PA1 (i) at least one aromatic diayl halide of formula EQU YOC--Ar.sub.1 --COY PA1 where --Ar.sub.1 -- is a divalent aromatic radical such as 1,4-phenylene, 4,4'-biphenylene, terphenylene, naphthylene, anthracenylene, and the like; Y is halogen, preferably chlorine; and COY is an aromatically bound acyl halide group, which diacyl halide is polymerizable with at least one aromatic compound of (a) (ii), and PA1 (ii) at least one aromatic compound of the formula EQU H--Ar'--H PA1 wherein H--Ar'--H is an aromatic compound such as biphenyl, terphenyl, naphthalene anthracene, or diphenyl ether; and H is an aromatically bound hydrogen atom, which compound is polymerizable with at least one diacyl halide of (a) (i), or
It is important to note that miscible blends of PAEK's with higher Tg thermoplastics, are a route of choice to resins having the desired high glass transition temperatures that are required in composites applications, provided of course, that the thermoplastics in question display good toughness and heat and chemical resistance.
Such preferred miscible blends are described in patent applications Ser. Nos. 945,799 now abandoned and 008,696; both filed in the name of James E. Harris et al., on Dec. 24, 1986 and on Jan. 30, 1987 respectively; titled "Miscible Blends of A Poly(Aryl Ether Ketone) and An Imide-Containing Polymer", and "Blends of a Poly(Aryl Ketone) and a Poletherimide" and both commonly assigned.
In order to achieve optimum properties it is important that the crystallinity of the material be developed as far as possible during the fabrication process. This is due to the fact that subsequent use of an article which can continue to crystallize in use can result in dimensional changes occurring in the article with consequent warping or cracking and general change in physical properties. Moreover, in some applications, it is important to achieve a uniformity of crystalline texture and to maximize the number of crystallites regardless of increasing the rate of crystallization.
Crystallization rates are often a problem with crystalline homopolymers, even with the highly crystalline poly(aryl ether ketones). Crystallization rates are even more critical in miscible blends containing a poly(aryl ether ketone and an amorphous polymer, such as for example, a poly(ether imide) or certain polyimides and poly(amideimides). The presence of the second polymer component retards crystallization and, hence, the development of optimum toughness, optimum chemical, and heat resistance.
It is, therefore, highly desirable to develop new rapidly crystallizing miscible poly(aryl ether ketone) blend compositions, while retaining at the same time, all of the other attractive features of this class of polymers.
European Patent Application No. 152,161 describes poly(aryl ether ketones) having high crystallization rates. This is achieved by providing the polymer with ionic end-groups. In another embodiment, fast crystallization is achieved by blending a poly(aryl ether ketone) which does not contain terminal ionic groups with a material having such terminal groups.